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We consider a variant of the best arm identification (BAI) problem in multi-armed bandits (MAB) in which there are two sets of arms (source and target), and the objective is to determine the best target arm while only pulling source arms.…

Machine Learning · Computer Science 2021-12-09 Ojash Neopane , Aaditya Ramdas , Aarti Singh

We study a novel variant of the multi-armed bandit problem, where at each time step, the player observes an independently sampled context that determines the arms' mean rewards. However, playing an arm blocks it (across all contexts) for a…

Machine Learning · Computer Science 2020-06-18 Soumya Basu , Orestis Papadigenopoulos , Constantine Caramanis , Sanjay Shakkottai

In multi-armed bandits, the most-explored arms are the most informative, while reward maximization typically pulls only the best arm. We study the tradeoff between identifying arm means accurately and accumulating reward, and present an…

Machine Learning · Computer Science 2026-05-04 Akram Erraqabi , Alessandro Lazaric , Michal Valko , Emma Brunskill , Yun-En Liu

In a fixed-confidence pure exploration problem in stochastic multi-armed bandits, an algorithm iteratively samples arms and should stop as early as possible and return the correct answer to a query about the arms distributions. We are…

Machine Learning · Computer Science 2025-02-04 Adrienne Tuynman , Rémy Degenne

Contextual bandits are widely-used in the study of learning-based control policies for finite action spaces. While the problem is well-studied for bandits with perfectly observed context vectors, little is known about the case of…

Machine Learning · Statistics 2022-02-03 Hongju Park , Mohamad Kazem Shirani Faradonbeh

The multi-armed bandit problem is a core framework for sequential decision-making under uncertainty, but classical algorithms often fail in environments with hidden, time-varying states that confound reward estimation and optimal action…

Machine Learning · Computer Science 2026-02-19 Jikai Jin , Kenneth Hung , Sanath Kumar Krishnamurthy , Baoyi Shi , Congshan Zhang

We present a two-armed bandit model of decision making under uncertainty where the expected return to investing in the "risky arm" increases when choosing that arm and decreases when choosing the "safe" arm. These dynamics are natural in…

Optimization and Control · Mathematics 2017-03-22 Roland Fryer , Philipp Harms

We consider nonstationary multi-armed bandit problems where the model parameters of the arms change over time. We introduce the adaptive resetting bandit (ADR-bandit), a bandit algorithm class that leverages adaptive windowing techniques…

Machine Learning · Statistics 2023-10-27 Junpei Komiyama , Edouard Fouché , Junya Honda

We consider the Multi-Armed Bandit (MAB) problem, where an agent sequentially chooses actions and observes rewards for the actions it took. While the majority of algorithms try to minimize the regret, i.e., the cumulative difference between…

Machine Learning · Computer Science 2021-09-14 Nadav Merlis , Shie Mannor

The stochastic multi-armed bandit has provided a framework for studying decision-making in unknown environments. We propose a variant of the stochastic multi-armed bandit where the rewards are sampled from a stochastic linear dynamical…

Machine Learning · Computer Science 2022-04-13 Jonathan Gornet , Mehdi Hosseinzadeh , Bruno Sinopoli

We study the best-arm identification problem in linear bandit, where the rewards of the arms depend linearly on an unknown parameter $\theta^*$ and the objective is to return the arm with the largest reward. We characterize the complexity…

Machine Learning · Computer Science 2014-11-05 Marta Soare , Alessandro Lazaric , Rémi Munos

We consider the classical multi-armed bandit problem with Markovian rewards. When played an arm changes its state in a Markovian fashion while it remains frozen when not played. The player receives a state-dependent reward each time it…

Optimization and Control · Mathematics 2022-11-15 Cem Tekin , Mingyan Liu

Motivated by the fact that humans like some level of unpredictability or novelty, and might therefore get quickly bored when interacting with a stationary policy, we introduce a novel non-stationary bandit problem, where the expected reward…

Machine Learning · Computer Science 2022-03-08 Pierre Laforgue , Giulia Clerici , Nicolò Cesa-Bianchi , Ran Gilad-Bachrach

We study a regret minimization problem with the existence of multiple best/near-optimal arms in the multi-armed bandit setting. We consider the case when the number of arms/actions is comparable or much larger than the time horizon, and…

Machine Learning · Statistics 2020-10-23 Yinglun Zhu , Robert Nowak

We study nonparametric contextual bandits where Lipschitz mean reward functions may change over time. We first establish the minimax dynamic regret rate in this less understood setting in terms of number of changes $L$ and total-variation…

Machine Learning · Statistics 2023-11-21 Joe Suk , Samory Kpotufe

We study fixed-confidence Best Arm Identification (BAI) in semiparametric bandits, where rewards are linear in arm features plus an unknown additive baseline shift. Unlike linear-bandit BAI, this setting requires orthogonalized regression,…

Machine Learning · Statistics 2026-04-07 Seok-Jin Kim

Social learning is learning through the observation of or interaction with other individuals; it is critical in the understanding of the collective behaviors of humans in social physics. We study the learning process of agents in a restless…

Physics and Society · Physics 2020-12-01 Kazuaki Nakayama , Ryuzo Nakamura , Masato Hisakado , Shintaro Mori

In this paper, we study a variant of best-arm identification involving elements of risk sensitivity and communication constraints. Specifically, the goal of the learner is to identify the arm with the highest quantile reward, while the…

Machine Learning · Statistics 2025-02-11 Ivan Lau , Jonathan Scarlett

In many applications, e.g. in healthcare and e-commerce, the goal of a contextual bandit may be to learn an optimal treatment assignment policy at the end of the experiment. That is, to minimize simple regret. However, this objective…

Machine Learning · Computer Science 2023-11-06 Sanath Kumar Krishnamurthy , Ruohan Zhan , Susan Athey , Emma Brunskill

Multi-armed bandit (MAB) processes constitute a foundational subclass of reinforcement learning problems and represent a central topic in statistical decision theory, but are limited to simultaneous adaptive allocation and sequential test,…

Methodology · Statistics 2026-02-27 Li Yang , Xiaodong Yan , Dandan Jiang